1. Field of the Invention
This invention relates to a portable forced air warming apparatus for warming victims of hypothermia.
Severe hypothermia is a surprisingly common occurrence in cold areas of the world. Hypothermia is considered to be severe when there is a significant risk of spontaneous ventricular fibrillation, which can result in death of the victim. The risk of ventricular fibrillation increases significantly when the victim""s core or deep body temperature is below 28xc2x0 C. At such low core temperatures, the victim should be handled carefully because of his/her unstable condition. A severe hypothermia victim who has been cooled rapidly, e.g. during immersion in water, is preferably rewarmed rapidly. A severe hypothermia victim who has been cooled slowly, e.g. by exposure to cold air, is preferably rewarmed slowly. In any event, it is imperative to stop heat loss and to initiate rewarming of victims of hypothermia as soon as possible to optimize the chances of survival. During rescue operations in remote areas, it may take several hours to transport casualties from the rescue site to a hospital for treatment.
2. Discussion of the Prior Art
Warming apparatuses, some of which are portable, are disclosed by U.S. Pat. No. 5,300,101, which issued to S. D. Augustine et al on Apr. 5, 1994; U.S. Pat. No. 5,304,213, which issued to L. D. Berke et al on Apr. 19, 1994; U.S. Pat. No. 5,336,249, which issued to I. Mahawili on Aug. 9, 1994; U.S. Pat. No. 5,350,417, which issued to S. D. Augustine on Sep. 27, 1994 and U.S. Pat. No. 6,001,057, which issued to R. A. Bongiovanni et al on Dec. 14, 1999.
The inventors have determined that when rewarming a hypothermia victim, it is preferable to heat the torso only while preventing heat loss from the extremities. Heating of the victim""s limbs causes the return of cold blood to the torso which contributes to a core temperature drop that can decrease the chances of survival.
Very few warming apparatuses are available in the marketplace, and those that do exist consist of heated blankets or bags for heating a victim""s entire body and extremities, and devices for providing warm air for inhalation by the victim. A need exists for a system for eliminating heat loss and initiating rewarming of a hypothermia victim in the field.
An object of the present invention is to meet the above need by providing a relatively simple, portable, forced air warming apparatus, which is easily transported to the field, and which can be used for controlled heating of a victim""s body.
Another object of the invention is to provide a portable warming apparatus which can be used to warm a victim""s body only while preventing heat loss from the extremities.
Yet another object of the invention is to provide a warming apparatus which can be used to effect controlled warming of the victim""s head and neck which contributes to warming of the central nervous system, and helps a victim to regain normal respiratory and cardiovascular functions.
In its simplest form, the invention relates to a portable warming apparatus for warming a hypothermia victim comprising a stretcher, said stretcher including a bottom wall, side walls and end walls contiguous with each other; a support extending between said side walls for supporting the body of a hypothermia victim, openings in said support permitting the circulation of warm air around the torso of the victim, a canopy for covering the torso of the victim and defining a heating chamber around the torso with said stretcher; at least one heating duct in said chamber for discharging warm air against the torso of the victim, whereby the warm air circulates through said openings around the torso; and a forced air heater for warming ambient air, and delivering the warm air to the heating duct.